1. College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, P. R. China
2. Department of Hepatobiliary Surgery, Hunan Provincial People’s Hospital, Changsha 410000, P. R. China
3. School of Biomedical Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia
4. Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan 48824, United States